Block system



Sept. 1

1941- M. H. LOUGHRIDGE 2,255,797

BLOCK SYSTEM Filed March 13, 1939 3 Sheets-Sheet 1 17, High p 1941- M. H. LOUGHRIDGE 55,797

BLOCK SYSTEM Filed March 15, 1959 3 Sheets-Sheet 2 P 1941- M. H. LOUGHRIDGE 2,255,797

BLOCK SYSTEM Filed March 15, 1959 3 Sheets-Sheet 3 1527 &

INVENTOR.

Patented Sept. 16, 1 941 I UNETED STATES grsnr -FFlCE 15 Claims.

This invention'relates to block systems for controlling traffic on a railway track and it is shown in connection with electric railways which are provided with a third rail or power conductor for An object of the invention is to superimpose the block system upon the power system so that trains may supplying propulsion current to the trains.

be continuously controlled as they move alongthe track. Another object of the invention is to impress a block circuit upon sections of the power conductor for controlling trains and to suppress this circuit by a controlling circuit connected with another section of the power conductor; another object of the invention is to provide a block system superimposed upon a power conductor which is divided into sections and which stops a train in the rear block when the next block'ahead is occupied, and which also stops the last train entering an occupied block; another object of the invention is to provide a block system superimposed upon a power conductor which is adaptable for trafiic in both directions on the same track; another object of the invention is to provide a selective block system superimposed upon a power conductor Without the use of moving apparatus on the trackway, and another object of lowing specification and the accompanyingdrawings, in which Fig. 1 is a circuit diagram showing one form of the invention operated by tuned circuits;

Fig. 2 is another form of the inventionoperated by rectified circuits and arranged to provide protection against a following train entering an occupied block;

Fig. 3 is another circuitv diagram in which the block current is supplied by a separate transmission line;

Fig. 4 isa diagram of the apparatus and circuit in Fig. 2 showing the operation onfa train in rear of an occupied. block;

Fig. 5 is a circuit diagram of a combined block system and power system appliedto a track for trafiic in both directions.

This system disclosed in Figs. 1 to 5 inclusive was originally disclosed in part in application Serial No. 594,771, filed February'24, 1932, now Patent 2,151,709 March 28, 1939. This application embodies the block system with the power distribution system in such a way that'contact wires or inductive devices for the block system itself are not necessary, while a continuous block contrel isobtained. According to established prac- "tice at the present time the operating power for electric carsis obtained from a trolley wire or from-a third railby contact, and the same contact 'canbe used to pick up the train control circuit "and selectively-operate a train control system Which-issuperimposed on the power wire.

Generally considered, this system comprises dividing the power wire-by the use of reactance devices in suchamanner as not to materiallyinterfere with the propulsion current, while, at the same time, -the train control current is limited by I these divisions. A current having a particular characteristic which isselectively different from the current in the power wire is superimposed on each section of the power wire :and'isa-rrangedto energize a train control relay ina-resonant circuit on the vehicle to permit the vehicle toproceed. The source of this current is con-trolled by a current having another characteristic-or frequency connected with the block ahead 'andis so arranged that a train in the block aheadsubstantially depresses, or deenergizes, the superimposed train control current "and therebycauses a train in the following block to 'be stopped.

The system uses currents of three different frequencies orcharacteristics, 1. e.: a) the pro- "pulsion'current has one characteristic; (h) the -=train controlcurrent has a second characteristic and (c) the bloc}; control current has a third "characteristic. 'For instance, the propulsion current-may be directcurrent or may be alternating currentof a commercial frequency, such as sixty "cycles per second. The train control current which is superimposed upon the power wire may have a frequency of at least one thousand cycles persecond, and the control of this circuit may be embodied in a circuit having one-half this freenemy.

The system is operated by providing a high frequency line with a transformer connected between this line and the running rails for each block. Thesecondary of this transformer is used to energize the primary circuit of a secondjtransformer and the secondary of the second transformer is used to energize a portion of the power wire in thejrear with train control current. The primary circuit of the second transformer is 'briclgedacrossthe power wireand the track rails.

"Each of the circuits are connected through con- 33 to ground on the running rails.

densers to establish a predetermined resonance. The vehicle is provided with a propulsion motor and a train control relay controlled by the train control current. This relay, when energized, permits the vehicle to proceed and when deenergized causes a brake application. A circuit is provided on the vehicle connected with the trolley wire which is resonant to the train control current and has a translating device embodied therein which is energized as long as this current is present in the power Wire. A controlling circuit is connected with the trolley contact which is resonant to the primary circuit of the second transformer and practically deenergize's or suppresses this circuit when the train is in the block, thereby effectively deenergizing. the,

power wire in the rear block of train control current, thus establishing conditions to stop the train in the rear block.

The track wiring In the drawings, the track rails are indicated by H, the power or trolley Wire is indicated by 2, a low frequency generator is indicated by l3 for energizing the power wire l2 and which is grounded on the track rails by wire I4. The power wire is divided into block sections, a, b and c by the reactances I511, shown as of the coil type. High frequency generator l6 energizes the transmission wire I! and has the opposite side grounded on the track rails by wire M. A transformer is provided for each block having a primary coil [8 connected between the high frequency transmission line if and the ground or rail return l9. provided with an output circuit from secondary winding 2| which energizes the input circuit of transformer 24 through coil 22. The secondary coil 23 in the output circuit of transformer 24 is grounded on one side through wires and [9 and on the opposite side connects through the condenser 26 and the line wire 21 to the block in the rear on the power wire 12.

The input circuit for primary coil 22 of transformer 24 is connected at one side to the ground This transformer is energized the motor circuit is established and the vehicle proceeds; when this relay is deenergized. the motor circuit is interrupted at and the Vehicle stops. The relay 34 may control the brakes as well as the power in a system corresponding with U. S. Patent 1,805,551, issued May 19, 1931 to M. H. Loughridge.

A primary train control relay 42 is controlled by the train control circuit connected with the trolley contact 32 and wire M) to coil 45, wire it, primary coil i? of transformer 49 and condenser 38 to the ground connection 33. This completes the train control circuit from transformer 2 1. The transformer d9, through condenser 59, energizes the coil 5| of relay 42. Relay 42, as shown, is of the motor type and when coils 5! and are energized with current in proper phase relation this relay closes the contact 4|, connecting wire 40 with 43 and energizing the train control relay 3 3 which connects by wire 44 with the return circuit at 33.

' in the train contr'ol circuit so that when high wires 25 and i9 and connects on the opposite 7 side through wire 28 and condenser 29 and wire 27 to the trolley wire. This connection is made to the block section of the trolley wire immediately in advance of the block section which is energized through the secondary coil23 of the output circuit of transformer 24. The circuits described connecting on :one side to the power wire l2 and on the opposite sideto the track rails are completed on the cars between conductors 32 and 33 and selectively operate appa- The car wiring The car wiring is indicated at 3! in which the conductor 32 picks up propulsion current from generator !3 on the power wire or third rail. This is controlled by contact 35 of train control relay 34, by wire 36 to motor 37 and by contact I This completes the propulsion circuit. When relay 34 is is grounded at 33.

frequency current is present in this circuit the relay 62 is moved to the energized position and thereby establishes the motor circuit to permit the vehicle to proceed. On the other hand, whenthis current is absent from a block section, or is substantially suppressed, the relay 42 is deenergized and the vehicle is stopped. 7

It will be observed that when a train is in the block the primary coil 22 cf transformer 24 is short circuited through condenser 29 by a circuit starting on wire 28, condenser 29, wire 2?, block section or power wire !2, trolley contact 32 on vehicle 3| and motor circuit to ground return through 33. and [9. Also when the train control'relay 34 is deenergized by a train in the block ahead a circuit is established through contact 35 and wire 38 with the condenser 39 which This establishes the block control circuit. The condenser 29 and the-condenser 39 are made resonant to each other, and the .condenser29 is also resonant to the motor circuit. The condenser 29 when thus connected in circuit with the vehicle circuit suppresses the primary circuit of 24 to such an extent that the rear block circuit fed by this transformer is substantially deenergized and the block in the rear is deprived of block current. The transformer 20 is preferably of the open circuit type so, that the output of the secondary is definitely limited.

The'reactance' coils. 15a are provided ,to substantially isolate the high frequency block current to each section of the power wire without .materially interfering with the power circuit whether it is energized by direct or alternating current; Reactances'for this purpose are commonly used in the art one form of which is shown in U. S Patent 905,327, December 1, 1908,. .1

train control current. for-the rear block is substantially suppressed, thetrain control current from .the next block ahead remains effective to energizethe train control relay and permit the train in the forward block to proceed while preventing a following train in the rear block from proceeding... It will be noted that current is required to produce the'proceed effect-thus operating by,the closed circuit principle. In operation, the static apparatus on the trackway 'remains energized electrically from the generators. When a train enters a blockwith the preceding "block-cleargthe train control relay 34 is energized through' the primary train control relay ei-which is energize'd by thetrain control ourrent' in the block section "which the train occupies. This conditioncontinues from block to block under 'clearconditions. Relay-3t energized, supplies propulsion current from the conductoriZ through-contact 32 to thepropulsion motor 37 thereby-providing for the continuous forward movement of the train.

-When a seccn'd train follows anothertrain and remains at leasta-clear block in rear of the leading train, it continues to moveforward from bleck-to-blo'ck in the same manner as the leading train on aclear track. -When-a following train closes-upon the train ahead by entering the block immediately in the rear of the trainahead, the train control relay t l on the following train is-deenergized because the train in the forward block has shunted the input circuit of transformer 24 and suppressed the train control circuit'of'theblockeccupiedby the following train. Relay =34 opens the circuit "of the propulsion motorand thereby "stops the following train, which, in ordinary practice is stopped within the block. When the'leading train moves on to the next block ahead'the shuntonthe input circuit of transformer-2d is removed, the train control current is restored to the block section of wire 12, this energizes the train control relay on the rear train and it resumes its normal running.

If the train in theforward block is stopped the shunt of the'input'circuit of transformerzd is maintainedthrough "35 and 39" to suppress the train-control current to the rear'block and stop the train in this block.

Selection by rectifier-s on the track Amo'dified arrangement" is shown in Fig. 2 in which the block-current is made selective by feeding through two sets of fullwave rectifiers with a corresponding increaseof frequency,-and the-vehicle circuitsare so-arranged that a train in the rear block is not only controlled by a train in'the-next blockahead butif the following train should enter an occupied block it will be stopped until 1 the train ahead occupying the block has moved out.

The track wiring includes the trolley wire :2 divided into blocksections a,-b, c by the coil type of reactance Iiia. The first transformer-2D is energized from the line wire I! by current of a higher frequency than the propulsion current in the trolley wire. The secondary coil-2I of transformer 25 connects to the full'wave rectifier dil and this rectifier, through condenser fil, energizes the second transformer 32 which is used to energize a third transformer 98 through the rectifier '91 and the'condenser 99 so that the frequency of the current output from the'secondary from transformer 98 is double that of current input of transformer 82 as will be understood from the diagram. The secondary of 98, throughcondenser 2'5- energizes the block circuit-2lwith train control current.

'In this arrangement the transformer MI is providedonthevehicle for the propulsion current, the secondary of which is controlled by the train control relay 34 to energize the motor I31 through contact 35. Relay l-lkgrounded-on one side "at 33, connects through-condenser I52, reactance "6 Landconductor '32 to the power *wire :12. The condenser tIZ is inresonance -w-ith"the condensertle so ithat relay IIA; is 1 energized from the-secondary coil- 2 I of transformer ziL-that is,

from the block I control "circuit, I the suppression current of the control circuit being suflicient to energize relay 5 I'M -while effectively suppressing the energy to transformer 92.

Atransformer II! has aprimary -coil, one side of Which isgrounded-at the other side conin'ects through wire-I iB -to conductor '32 and for tuning purposes, a second condenser I 9 may be bridged acrosszthis coil as. shown. The second- .ary. of transformer I I1; through circuit I t6, .energizes' 'relay H5. LThlS circuit is resonant to .the train control current from oondenser ZIi and relay IIl'apis energized when train control Jour- .rent'ispresentand is deener'gized when the train control current: is suppressed.

A stick relay I2Ilis provided to insure that a train receiving a proceed effect in a block from the train control. circuits will-not be influenced by a following'train entering the :same block. Relay I20 is energized from battery I2I, through contact I22 of relay 1 I i-energized, wire I23, relay I29 and wire I24 to battery. The-stick circuit 7 of relay IE9 is maintained through contact I27, :wire I26'and contact'I25 of relay H5 to battery. The blockrelay34 is energized from battery I25 through contact I28 of relay H5, Wire'IZQ, contact I38 of relay 12%, wire 53!, relay .34 and wire I24 to battery.

In operation, when the next block ahead is clear, the relays H4 and H5 are energized, the stick relaylZfiis energized-and the'train control relay 34 is energized enabling the train to .proceed. When another train enters the blockin rearof an occupied block the relay I I5 on the rear trainis deenergized also relay 34 which opens the motor circuit and, normally, the rear train is controlledv and stopped within the rear block where it remains until the block ahead clears and theltrain' control current is restored to the block sections. Should the rear train, for any reason, "overrun the block and enter the block ahead already occupied by another train, this 'would'put a second shunt on'the'control circuit and thereby would deenergize relay H4 in both of the trains occupying the same block due to the limited output of 2|. In the'rear train, however, the relay I I 5 was deenergized when the occupied block was entered and. this relay is made slow acting'in its pick up so thatrelay H4 becomes 'deenergized before relay H5 can pick up, thereby deenergizing the stick relay I26 on the rear train and maintaining the train control relay-34 deenergized to stop this train. As relayI I4 controls the pick-up circuit of the stick relay E29, it is apparent that I29 cannot become-energized after the relay H5 is energized until relay IN is again-energized. It will be noted, however, that on the advance train already in-the block relay H5 is energized and the holding circuitof relay I29 is thereby established so that should relay M4 on this train become deenergized it would have no effect on the control of the train. This enablesthe first train-to continue its journey whilethe second train is controlled until the track clears. A railway system having superimposed frequencies on a track circuit is shown in U. S. Patent 1,626,928.

Relays ll and I20 are provided for the control f .a following train. in the same block with another train. Where this control is not desired; these relays are omitted and the primary train control relay I I5 controls the secondary train controlflrelay 34 by the circuit on wires I29 and I3I, omitting the control by relay I 29.

'In the arrangement described, frequency changes on the trackway were obtained by static apparatus. It is apparent, however, that a wider range of frequency to distinguish between the block control circuit and the train control cirused to energize relay I04 through rectifier 90 controlling the block control circuit. Relay I04, by contact I03, connects the block wire 21 with the transmission line IDI through the condenser I02. A transformer, however, may be substituted for this condenser where the design of the circuit shows that a transformer is preferable.

Wayside apparatus responding to the presence of block current in the power Wire may be provided as indicated by the relay I44 which, throu h the transformer I42, is connected with the power wire I2 by connection I40, condenser MI, and is connected to the ground return wire I43. The condenser MI is made resonant to the current in the train control circuit controlled by condenser I02. Relay I44 controls the translating device I46 to show the condition of the block. The electric device I46 controlled by relay I44 may be alight bulb giving an indication for the purpose. desired.

Thetrolley wire 32 is connected with ground 33, through condenser I35 and conductor 33. This effectively suppresses the input circuit of rectifier 90 through condenser 29 and deenergizes relay I04 and the rear block of train control current. Relay I36 connects through transformer III the primary of which is grounded on one side at 33 and connects with condenser H9 and conductor 32 on the other side to respond to the train control current in the transmission 1mg IEII. Relay I33 closes the circuit of relay 34 through wire I38, contact I31, wire 32, to the power wire I2 and return through I24 and ground contact 33.

The operation of the system in Fig. 3 corresponds with Fig. 1. A train in the block shunts the input circuit of rectifier 90 thereby deenergizing the rear block of train control current by deenergizing relay I04. A train entering the rear block at this time will have its train control relay 34 deenergized owing to the, absence of train control. current in this block. This stops the rear train until the block ahead is cleared and the shunt removed from rectifier 99. c

It should be understood that the circuit is regarded as deenergized when the translating device in the circuit has changed its position or ceases to operate in the manner in which it operates when normally energized, although the circuit itself may not be deenergized in the sense in which it would be deenergized if the circuit were open. v

The block system herein disclosed has been shown in connection with an electric propulsion system, It isto be understood, however, that the block system may be applied by itself to trains that have self-contained motive power. It is alsoto be understood, that in the latter, case block sections of the block wire can be nsulated circuits.

from each other, thereby simplifying the electric apparatus.

The apparatus and'circuits in Fig. 4 correspond with Fig. 2 and operate in the same man-' this invention should be designed for the circuits in which the apparatus is used. This depends upon the character and the extent of the current necessary for propulsion purposes, the length of the block sections and the frequency of thecurrent in the train control circuit, also the frequency of the current in the block control circuit. The figures used in describing the system are arbitrary figures for illustration only.

Single track operation A system designed for single track operation is shown in Fig. 5. In this arrangement, in addition to using resonant circuits, a change of frequency is obtained between the train control circuit and the block control circuit in which the frequency of the train control circuit is double that of the block control circuit thereby insuring greater reliability in the selection of control between the block control and the train control This system also includes a line controlled relay which changes over the train control conductor from the block in the rear to the block in advance, or vice versa, according to the established direction of traffic, thus adapting the system for trafiio in both directions on the same track.

The power wire I2 is provided with reactances I 5a of the coil type for separating the block sections and may be energized with direct current. The output circuit of secondary coil 2| of transformer 20 energizes the transformer 92 through the full wave rectifier 90 and the condenser 9I. The secondary of transformer 92, by reason of the full wave rectifier 90, has twice the frequency of the current in the secondary coil 2 I. The secondary of transformer 92 connects through condenser 93 with the contact finger 88 of line relay 86. When this contact is in the left hand position as shown, wire 21 to the left is energized from transformer 92 and connects through the contact finger 89 of relay 86 in the next block and through wire 94 to the block section of the power wire. This energizes theblock section with train control current.

When the contact fingers of the line relays 84 are moved to the right hand position, the transformer 92 is connected with the line wire 27 to the right and the line wire 21 from the left connects to the block section of the power wire by wire 94. Relays 86 thus establish conditions for trafiic in either direction. I The line relays 83 are polarized and the contact fingers88 and 89 are swung to the right or to the left in accordance with the polarity of the circuit energizing these relays. This circuit established through line wire is controlled by manually operated switch 84 which, in one position, connects to battery 82 and in the other position connects to battery 83. These batteries are of reversed polarity and are grounded on the track-rails throughwire 8I. The relays 86 are grounded through connections 81 and It; This enables the direction of 1 traflic to* be established by'the-position of switch 8.4; When it'is desired to control the-train control circuit by any trackway condition; as, forinstance by the position of a'- trackwayswitch, this control may'be' obtained'by'aswitch 27a in wire-2l connected with the-controlling function;

The vehicle circuitin Fig, 5-includes a reactance 6| in the trolley conductor 32 and a- C0117 denser 62in series with the reactance 61! .connecting-to the ground atv 33;. The; transformer E l-is connectedto, conductor 32 abovethe-reactance 6| and-is-grounded-by wire 66; a condenser 65- is bridged across: the: primaryof this-transformer; The output circuit of secondary-coil Bl of transformer B l-is connected to: the, grid 68 of, an electron amplifier, the opposite side being connected to filament?! which is heated by battery iii; A' circuit is established'from'the plate of this amplifier through conductor 12; condenser 13' and reactance T4; in' multiple; battery" 15, transformer-l6; and return to the electron tube through the filament in' accordance I with established: practice. This energizesgsecond-ary coil l"! which; through;-re,ctifier; l8-and=circu it;19; energizes the traincontrol? relay 34, permitting, the vehicle, to, proceed;

The condenser" 62; is resonant to'the control circuitincludingthe condenser Bend the condensers 651 and 13:are resonant to the "train contIOlrCiITCllit including condenser 93;; With a train in-blockxb; for-instance; the" block control circuit issuppressedby ashunt'place on the-input circuit' of transformer 92' through wire 28; condenser 29, wire -95; blocksectionb', conductor 32, reactance 61-, condenser 62-; and-ground return by 33 and I9; At the same time the; train control current in-sectionbrbeing of a higher frequency thanthe-block current, is opposed by reactance GI' and; energizes the traincontrol relay 34:

through the amplifier; This permits a train to proceed in block-,bwwhilethe block, current to train: control -a:issuppressed; duev to the, shunting'of-theinput circuittof transformerfiZ; Thus atrainin; blocka will be stopped While anothertrainoccupies block b when: trains; is moving from left toright.

When switch 84 is reversed the armaturesof the relays 85at each location are. reverse'd'or moved to the right hand position to. adjust the system for trafiic from; right to left. Inthis case the train control, current. from 92: controlled: by contactgfinger 88.c0nnects to conductor 21', leadingto. the right, andthrough contact finger 89;

of; relay Eiiinthe nextblockto the'ri-ghtit iconnectsto theblock section ofthe power conductor- I 2 by wire 94. In this-case a, train in, block a for instance moving towards the left" shunts the block circuit from SZithroughxBlfirto; the right" and wire 2'! which is feeding. block b-tothe right by:

28,, 2,9, 95, 925-, through the vehiclercircuit andfreturnby wire. l9, so that a following trainrin block b is stopped until block aclears.

Having. thus describednmy' invention, I claim: 1; In a, block system, a railway track, a: power conductor adjacent said -track,,reactancesi operatively associated with said conductor dividing said conductor into, block sections, a source of alternating current supply, a transformer con,-

nected with said supply, a block control circuit energized by said transformer and connected to asection of said-power conductor, a train control circuit having cur-rent with'a characteristic, difference; from the current in said-controlling circuit andcontrolled by said controlling circuit and connected tov a block. section of saidpower conductor adjacentthe section energized by said block-control circuit, theother side of said c0ntrolling circuit and said block control circuit being: connected to -the track,- a vehicle on said track operated by said power conductor, a circuit on said vehicle cQ-operating with the section of said power conductor and completing the circuit between said conductor and'thetrack and to which i the: controlling circuit-is connected for suppressing said controlling circuit, and means on-the-vehicleiresponsive to the current-in said train control circuit controlling the operation of said vehicle.

2. In a bloclc system, a railway track, a conductor adjacent said track electrically divided into sections, means: for energizing each section withtraincontrolcurrent ofaparticular characteristic, means for energizing each section with blockcontrol current having a second; character,- istic,v eachofsaidmeans connected on one side to the track, said block control current for one section controllingthe train control current for anadjoining section; a vehicle on said'track having-a circuit including a secti0n:0f said conductor and'completing the circuit between said conductor and the track, and-means in the vehicle circuit selectively responsive to said train control current and controlling the movement of the vehicle on the track, said block control current being shuntediby said vehicle circuit.

3. In ablock system, a railway track, a conductor adjacent said track electricallydivided into sections; means for'energizing eachsection' with train control current of a particular characteristic and with block controlcurrent having a different characteristic, each. of said means connected'on one" side'to the track, said block control current controlling the train: control current for an, adjoining block, a vehicle on the track having a circuit including: a section of said conductor completing the circuit between the conductor and the, track; and translating m'eans in,said-,-vehicle circuit selectively responsive to said traincontrol current for controlling the operation" of thevehicle, said block control current being shunted by said-vehicle circuit;

4. In a, block system, a railway track, a con ductoradjacent said track electrically divided into sections, means for energizing each section with train control current of a particular characteristic and with blockcontrol current having'a different characteristic, each of said means connected on one side with the track, said block control current controlling the train control current, fora different section of said conductor than the section which it energizes, a vehicle on the trackhaving a circuit completing the circuit between said conductor and the track, means in the vehicle circuit cooperating with said block control current for deenergizing the train control circuit, and translating means on' the Vehicle selectively responsive to said train control-current controlling. the operation of the vehicle.

5. In a block system; a railway track, a conductor' adjacent said track electrically divided into-sections, a train control circuit for energizing each block section with current of a particular characteristic, atransformer for energizing said train control circuit connected on oneside-with the track, an input circuit for said transformer having; controlling current of a different characteristicfrom said train, control circuit, one side of said input circuit connected to the track and the other side connected to an adjacent section of said conductor from the section energized by the train control circuit, and a vehicle on said track having a circuit co- 1 operating with each section of said conductor to complete the circuit of the controlling current to the track, thereby suppressing the input circuit of said transformer and deenergizing the train control circuit. v

6. In a block system, a railway track, a conductor adjacent said track electrically divided into sections, a source of high frequency cur-- rent, a first transformer connected with said source and having a first output circuit, one side of which is connected with a section of said conductor and the other side is connected to the track, a second transformer energized from said first output circuit and having a second output circuit, a train control circuit for energizing the section of said conductor adjacent the section connected with the first output circuit and energized from said second output circuit, a vehicle on said track having a circuit completing the circuit between said conductor and the track and completing a shunt for the first output circuit to deenergize the train control circuit.

'7. In an electric railway system, the combination, a conductor adjacent the trackway supplying current for propulsion purposes, means electrically dividing said conductor into block sections, a train control circuit superimposed on each section of said conductor, a transformer having a' first output circuit for energizing said train control circuit, an input circuit for energizing said transformer with current having a characteristic diiferent from said train control current, said input circuit connected on one side with a section of said conductor adjacentthe section energized by said first output circuit and connected on the other side with the track, and a vehicle on the track operated by said propulsion current and having a circuit with a translating device controlling the vehicle and completing the train control circuit from said conductor to the track and completing a shunt circuit from said input circuit to deenergize the train control circuit.

8.'In an electric railway system, the combination, a conductor adjacent the trackway supplying current for propulsion purposes, means electrically dividing said conductor into block sections, means for superimposing on each block section a train control current having a particular characteristic, means for superimposing on each section a block control current havinga characteristic different from the train control current and the propulsion current and controlling the train control current for an adjoining block, each of 'said means connected on one side with the track, a vehicle on the track having a motor operated by said propulsion current and having a circuit between said conductor and the track, and means in the vehicle circuit selectively responsive to said train control current for controlling the vehicle motor, said vehicle circuit shunting said block control current.

9. In a block system, a railway track, means electrically dividing the trackway into blocks, a train control circuit on the trackway energized by current of one frequency, a block control circuit 'on the trackway energized by current of a lower frequency and controlling said train control circuit for an adjacent block, said train control circuit and said block control circuit ea h connected on one side to the track, a vehicle on said track having a circuit, means establishing electrical connection between the vehicle circuit, said train control circuit and said block control circuit, a translating device in the vehicle circuit selectively energized by said train control circuit and controlling the vehicle, and means in the vehicle circuit for shunting said block control circuit to deenergize the train control circuit.

10. In a block system, a railway track, a power conductor on the trackway, electrical means associated with said conductor dividing it into block sections, a transformer energized by alternating current, a block control circuit energized by the output circuit of said transformer, a train control circuit controlled by said block control circuit and energized by current differing in character from said controlling circuit, means connecting said train control circuit to one section of said power conductor, means connecting one side'of said block control circuittothe section of said conductor in advance of the section to which the block circuit connects and the other side to the track, a vehicle on said track connecting with said power conductor, a propulsion motor on said vehicle energized by current from said power conductor, a train control relay controlling said motor, a circuit on said vehicle connected with said power conductor attuned to said block circuit and controlling said train control relay and a second circuit on said vehicle connected with said power conductor attuned to said block control circuit and arranged to shunt said block control circuit to deenergize said train control circuit.

11. In a block system, a railway track, apower conductor on the trackway, electrical means associated with said conductor dividing it into block sections, a limited output transformer, energized by alternating current on the trackway, a block control circuit energized by said transformer, a train control circuit controlled by' said block control circuit and energized by current differing in character from said block control circuit, means connecting said train control circuit to one section of said lower conductor, means connecting said block control circuit to the section of said conductor in advance of the s section to which the train control circuit connects, .a vehicle on said track having a circuit connecting with said power conductor, a propulsion motor on said vehicle energized through the vehicle circuit by said power conductor, a train control relay controlling said motor, a circuit on said vehicle connected with said power conductor attuned to said train control circuit and controlling said train control relay and a circuit on said vehicle including said power conductor and the railway track shunting the out-' put of said transformer.

12. In a block system, a railway track, a power conductor on the trackway, electrical means associated with said conductor dividing it into ,block sections, a transformer energized by alternating current on the trackway, a block control circuit energized by the output circuit of said transformer, a train control circuit controlled by said block control circuit and energized by current dilfering in character from said block control circuit, means connecting said train control circuit to one section of said power conductor, means connecting one side of saidblock control circuit to the section of said conductor in advance of the section to which the train control circuit connects and the other side to the track, a vehicle on said track having a circuit connecting with said power conductor, a propulsion motor on said vehicle energized by said power conductor, a block relay, a shunt relay and a stick relay on said vehicle, said train control relay being energized by said train control circuit, said shunt relay being energized by said block control circuit and said stick relay having a pick-up circuit controlled by said shunt relay and a stick circuit controlled by said train control relay and the circuit of said motor being established by said stick relay and by said train control relay in the energized positions.

13. In a block system, a railway track, a power conductor on the trackway, electrical means associated with said conductor dividing it into block sections, a transformer energized by alternating current for each block, a block control circuit energized by the output circuit of said transformer, a train control circuit controlled by said block control circuit, and energized by current differing in character from said block control circuit, means connecting said train control circuit to a section of said conductor, means connecting one side of said controlling circuit to a section of said conductor and connecting the other side to the track, the block control circuit being connecting to the section in advance of the section where the train control circuit connects, a vehicle on the track having a circuit connecting with said power conductor, a propulsion motor on the vehicle, a train control relay controlling said propulsion motor, a circuit embodied in said vehicle circuit controlling said train control relay connected with the train control circuit in said conductor, a shunt circuit for said block control circuit connected with said conductor and means on each vehicle controlled by said train control relay for stopping the vehicle when it enters a block already occupied by another vehicle.

i l. In a block system, a railway track, a power conductor on the trackway, electrical means associated with said conductor dividing it into block sections, a transformer energized by alternating current, a second transformer energized from the output circuit of the first transformer through a rectifier, a train control circuit energized from said second transformer and connected with a section of said conductor, a block control circuit connected in shunt with the output circuit of said first transformer before it is rectified, connected on one side with the section of said conductor ahead of the section connected with the train control circuit and on the other side with the track, a vehicle on the track having a circuit connecting with said power conductor, a propulsion motor on said vehicle, a circuit on the vehicle having a train control relay energized by said train control circuit controlling the circuit of said motor, and a selective shunt on said vehicle for said block control circuit.

15. In a block system, a railway track arranged for traffic in both directions, a power conductor on the trackway, electrical means associated with said conductor dividing it into block sections, a line conductor, a relay connected with said line conductor for each block,

I a transformer energized by alternating current,

a second transformer energized by the output circuit of the first transformer, a train control circuit energized by the output circuit of the second transformer, a block control circuit energized by current difiering in character from the train control circuit, connected on one side with a section of said conductor and on the other side to the track, said train control circuit controlled by said relay and connected to said conductor so that the train control circuit connects to a section immediately in rear of the section where the block control circuit connects for trafiic in either direction on the track, a vehicle on the track having a circuit connecting with said power conductor, a propulsion motor on said vehicle, a circuit on the vehicle having a train control relay energized by said train control circuit controlling the circuit of said motor, and a selective shunt on said vehicle for said block control circuit.

MATTHEW H. LOUGHRIDGE.

. CERTIFICATE or CORRECTION. a

Patent No. 2,255,797 7 7 September 16, 19L 1.

MATTHEW H. LOUGHRIDGE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 6, sec- 0nd coltmn, line 14.7, for "lower" read -power-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 17th day of February, A. D. 19L 2.

7 Henry Van Arsdale, (Seal). Acting Commissioner of Patents. 

